Auxiliary supply for alternatingcurrent systems



Sept. 1937- H. E. WARREN 2,094,481

AUXILIARY SUPPLY FOR ALTERNATING CURRENT SYSTEMS Filed Feb. 25, 1956 Fil.

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Patented Se t. 23, 1937 UNITED STATES AUXILIARY SUPPLY FOR ALTERNATING-CURRENT SYSTEMS Henry E. Warren, Ashland, Masa, assignor to 'WarrenTelechron Company, Ashland, Mass.

a corporation of Massachusetts Application February 25, 1936, Serial No.65,610

3 Claims.

My invention relates to an auxiliary supply for alternating-currentsystems, particularly systems requiring a limited amount of power, suchas alternating-current clock systems, and its ob- Ject is to provide areliable, inexpensive source of regulated frequency alternating currentand an automatic change-over relay system therefor, whereby theauxiliary source becomes substantially instantly available whenever thenormal source of supply fails. The auxiliary source may receive itsenergy from a direct-current supply, such as a storage battery. In orderto convert such direct-current supply into regulated frequencyalternating current, I use a simple vibrating reed converter and atransformer. The relay system, which is responsive to the voltage of thenormal source of alternating-current supply, serves not only to changethe connections of the supplied system from one source to the other asthe conditions demand but also serves to start and stop the vibratingreed converter and make the necessary changes in the direct-currentconnections associated therewith to prevent waste of direct-currentenergy when the regular alternating-current supply is available.

The features of my invention which are believed to be novel andpatentabie will be pointed out in the claims appended hereto. For abetter understanding of my invention, reference is made in the followingdescription to the accompanying drawing in which Fig. 1 shows the partsand'circuit connections employed in carrying my invention into effect;and Fig. 2 shows the same general arrangement with a somewhat differentrelay contact arrangement.

Referring to Fig. 1, [0 represents a normal source ofalternating-current supply and H a system which is normally suppliedthereby, such, for example, as a synchronous motor driven clock system.In case no auxiliary supply is available, the clocks or other devicesconnected to system II will stop should the supply Ill fail for anyreason. Such failures are not likely to happen often or to be of longduration but it is, nevertheless,

,45 desirable to provide a reliable auinliary source of supply whichwill become substantially instantly available to supply the clock systemat the proper frequency to keep the clocks in operation withoutappreciable error so as to maintain cor-- rect time service in case ofsuch a failure. Such auxiliary supply apparatus may not be called uponto function more than a few minutes during a year, consequently, itshould'be as low in cost as is possible.

To prevent-waste of energy, the auxiliary apparatus should be normallyde-energized but should be of such character as to start into operationvery quickly in response to a failure in w the regular supply and togenerate alternating current at the correct frequency and voltage forthe clock system during the period of failure of the regular supply andthen transfer control to the regular supply as soon as it is availableand restore itself to the idlede-energized condition in readiness forthe next emergency. v

The auxiliary apparatus represented in Fig. 1 fulfills theserequirements and its main parts comprise a contact relay l2 having itsoperating coil l3 connected to and responsive to the regular source ofsupply ill, a vibrating reed contact device ll having its operating coilI 5 supplied from an ordinary six-volt storage battery l6, and atransformer I] having low-voltage primary winding coils I8 and I9supplied by impulses from the storage battery It through the contacts ofthe vibrating reed device, and having its secondary winding 20 connectedthrough contacts controlled .by relay l2 of the clock system H.

The relay I2 serves a double function, namely, to transfer theconnection to the system I I from the regular supply Hi to thetransformer secondary 20 and vice versa, and to energize and deenergizethe vibrating reed converter, both functions being responsive,respectively, to the failure and resumption of the regular supply Hi,and by a failure I mean to include a drop in voltage of the regularsource below that which will give satisfactory service.

Relay l2 comprises the stationary magnetic core 2| energized by the coill3 and a movable magnetic armature 22 pivoted or resiliently supportedat 23 for operating a contact member .22 connected to one side 24 of thesystem H. Ar-

mature contact member 22', when in the deenergized position, is biasedto rest against a stationary contact 25 connected through a condenser 26to one terminal of the secondary winding 20 of the transformer ll. Theother terminal of the transformer winding 20 is connected to that sideof the line ll, which constitutes a permanent connection between oneside of the regular supply system l0 and one side of the clock systemll. When the relay I2 is energized, its movable contact 22' moves awayfrom contact 25 and rests against another stationary contact 21 which isconnected to the other side of the regular supply In. It will thus beseen that, when the supply Ill fails and relay I2 is de-energized, theclock system H is connected to the transformer winding 20 anddisconnected from source Hi. When the supply In is available, relay I2is energized and system H is connected to supply It and disconnectedfrom the transformer.

I The armature 22 of the transfer relay I2 also operates a hookedextension 28 which co-operates with one of the contacts 29 of thevibrating reed device It. Contact 29 is resiliently supported at 30 and,when released by the hook 28, assumes a position where it will contactwith the movable armature member 3| of the vibrating reed when thelatter isin its neutral or idle position. when,

however, relay I2 is energized, the hook 23 withdraws contact 23 so thatit is out of reach of the armature 3| even should the latter bevibrating. With the connections to be explained, it will appear thatthis feature serves respectively to energize and de energize thevibrating reed device in response to a failure and resumption of theregular source of supply Ill.

The vibrating reed device consists of a U- shaped stationarymagneticcore 32 on which the energizing coil I5 is wound. The reed 33 is securedat its upper end 34 to the upper extremity of the core 32. The reed 33is of'resilient magnetic material and carries the magnetic contactmakingarmature 3| at its lower end adjacent to the lower limb of the core 32.The period of vibration of the reed 33 and armature 3| is made tocorrespond to the normal frequency of the clock system H and thevibrating member preferably carries an adjusting screw 35 to make thisfrequency of vibration exactly correct. The amplitude of vibration ofarmature 3| is also preferably made adjustable by making the lower limbof the magnet core'32 in the form of an adjustment screw 33, serving asa stop between the lower extremity of the core piece 32 and armature 3|.The tip of this magnetic screw 33 may be faced with nonmagneticmaterial, if desired.

On the opposite side of armature 3| from con tact 29 previously referredto, there is another .relatively stationary contact 31 which isresiliently supported by a stationary part of the structure, not shownin detail. The contacts.23 and 31 or the co-operating contacts onarmature 3| will preferably be adjustable to adjust for best conditions.It will be understood that, when the armature vibrates, contact isalternately made and broken with contacts 23 and 31 if the transferrelay I2 is de-energized and that, in the idle or rest position of thearmature 3|, it will rest lightly against contact 23 when the transferrelay i2 is de-energized. In case 'relay I2 is energized, contact 23 iswithdrawn far enough so that the armature 3| does not make contacttherewith even if vibrating.

The coil |5 of the vibrating reed device is connected, as shown, so asto be energized from the storage battery l3 through the reed 33 andcontact 23 when the latter is in contact with armature 3|. The primarycoil l3 of the transformer is connected, as shown, to be energized inparallel with coil l5 when the contact at 23 closes. The other primarycoil l3 of the transformer is connected, as shown, to be energized fromthe storage battery l6 when the vibrating reed armature 3| makes contactat 31. Coils l8 and I3 may be considered as a single winding which has amiddle tap permanently connected to one side of storage battery "5. Theother side of the battery is permanently connected to the vibrating reed33. The alternate impulses flowing through coils l3 and i3 produce.fluxes in the transformer core which are in opposite directions.

A. condenser 33 is preferably connected across the contacts 23 and 31.The resiliency of the supports of these contacts tends to prolong theduration of contact slightly. The condenser 33 and the condenser 23 inthe secondary of the transformer tend to smooth out the current and fluximpulses so that a satisfactory alternatingcurrent wave is supplied tothe clock system II when the auxiliary apparatus is in operation. In

the arrangement described, a complete oscillation or back and forthmovement of the vibrating armature 3| corresponds to a complete cycle ofalternating current as produced at the secondary terminals of thetransformer. The invention is not confined to this relationship,however. The relation of turns in primary and secondary will be such asto produce the proper operating voltage for system H.

' Operation no energy. Armature 3| will be at rest with both contacts 23and 31 open so that no current is drawn from the storage battery l6 whenthe apparatus is in this condition and all windings of the transformerare de-energized.

Let us assume now that the power supply at I3 fails. This de-energizesrelay l2, its armature swings to the left and the following circuitchanges occur simultaneously. Contact between 22' and 21 is broken,disconnecting system H from source l0. Contact is made between 22' and25 connecting the secondary winding 20 of transformer H to system H. andmoves into contact with armature contact 3| of the. vibrating device,thereby energizing coil l5 and, at the same time, sending a currentpulsation through primary coil IQ of transformer l1 which appears at theterminals of the secondary winding as the first half cycle of the ailiary alternating-current supply. Armature 3| meanwhile is drawn to theleft by the magnetic pulsation in core 32, opening contact at 23 andclosing contact at 31. This de energizes coil l3 of the transformer andcoil |5 of the vibrating relay and energizes coil l8 of the transformer,sending a current pulsation therethrough which is reflected at theterminals of the secondary winding 20 as the next and reverse halt cycleof the auxiliary supply. Armature 3| springs away to the right, openingcontact at 31 and closing contact at 23 and continues in vibration,repeating the cycle of operation iustrdescribed' at a rate which isadjusted to produce correct frequency alternating-current for .the clocksystem The transformer ratio is, of course, such that normal voltage isalso available on system M.

It will be evident that the auxiliary supp y becomes'available atcorrect voltage and frequency pfactically'lnstantaneously following afailure of inexpensive and there is no drain on the storage battery I6except when theauxiliary supply is in use and then its energy isefficiently used. resilient support of the various contacts assures aslight wiplngcontact action which is desirable and the slight shock ofthe vibrating relay device is beneficial in case dust has collected andthe parts tend to stick due to the normally idle condition.

when the regular supply at I0 is resumed, relay I2 is energized, openingcontact at 25 and closing contact at 21, connecting system H to sourcel0, and disconnecting the transformer. Contact 23 is pulled away so asto prevent contact between it and armature 3|, which then stopsvibrating, leaving all circuits supplied by Contact 29 is released wherea regulated frequrncy is used battery l6 open. This change-over is alsoaccomplished without loss of time. An occasional inspection of theapparatus and recharging of battery iii, if a battery is used, is allthe'attention which the apparatus should require.

In Fig. 2, the parts of the apparatus which are similar to Fig. l areindicated by like reference characters and should need no furtherexplanation. The contact corresponding to 29 of Fig. 1 has beenseparated into two contacts 40 and 4| in Fig. 2. Contact 40 isresiliently supported and is connected to supply transformer coil l9.Contact 4| is resiliently supported and is connected to supply coil l5of the vibrating relay device.

These contacts may now be independently adjusted to positions bestsuited for their different functions. The time and duration ofenergizing the operating coil i5 for the vibrating relay can be changedwithout disturbing the position of contact 40 and likewise the durationof the-pulsation of transformer energization through contact 40 may bechanged without disturbing contact 4|. Contact 4| is withdrawn by relayI! when the latter is energized to stop operation of the vibrator as inFig. 1.

In Fig. 2, the secondary winding-20'may be connected and controlled thesame as in Fig. 1, but a slightly different arrangement is shown.Transformer I1 is permanently connected to the system il in parallelwith condenser 42 and the contact 25 of relay l3 (Fig. l) is omitted.Very little energy is fed back through the transformer to condenser 38under normal conditions when the source I0 is available with thisarrangement because with condensers present the arrangement constitutesa-tuned circuit. Both the arrangements of Figs. 1 and 2 have been; foundto be satisfactory. The separation of the contacts 40 and 4! in Fig. 2offers some slight advantage in adjustment.

Although the invention has been described as an auxiliary supply for aclock system, it may be used as an auxiliary supply for other purposes,such, for example, as signalling systems and service interruptions areto be avoided.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means. 1

What I claim as new and desire to secure by Letters Patent of the UnitedStates is: I

1. An auxiliary source of alternating-current supply comprising atransformer having primary and secondary windings, a direct-currentsource of supply therefor, a vibrating reed contactor interposed betweensaid direct-current source and the primary winding of said transformerin such manner that, when the vibrating reed contactor is in operation,.an alternating current of a desired voltage and frequency may besupplied from the secondary winding of said transformer, anelectromagnet for operating said vibrating reed contactor, and a circuitfor energizing said electromagnet from said direct-current sourcethrough said contactor, said energizing circuit including a resilientlymounted contact which is movable towards and away from the vibratoryelement of said contactor inclusive of positions a where contact is madewhen the vibratory element of. the contactor is idle and at oneextremity v of its swing when it is vibrating, and where no contact ismade under either condition.

2. In combination with a regular source of alternating-current supplyand a load circuit supplied thereby, an auxiliary source for supplyingsaid load circuit when the regular source fails comprising adirect-current supply, a vibrating reed contact device and a transformerhaving primary and secondary windings, connections for supplying the-primary of said transformer by impulses from the direct-current supplythrough the vibrating reed contact device such that alternating currentof the desired frequency may be supplied from the secondary winding ofsaid transformer only when the vibrating reed device is in operation,said vibrating reed device having a vibratory contact and a pair of.relatively stationary contacts between which the vibratory contactoscillates when in operation and through which the impulses to saidtransformer are supplied, an electromagnet for operating said vibratorycontact device, which electromagnet is energized through the vibratorycontact and one of the relatively stationary contacts, and relay meansresponsive to the voltage of the regular alternating-current supply forshifting the position of the relatively stationary contact through whichthe electromagnet is supplied so that the electromagnet will beenergized in the idle position of said vibratory contact when theregular source fails and will be intermittently energized as long assuch failure persists when the vibratory reed is in operation, and willcease to be energized for all conditions of said vibratory contact whenthe regular source of supply is resumed.

3. In combination with a regular source of alternating-current supply, aload circuit normally supplied thereby, and an auxiliary source forsupplying said load circuit at the desired frequency during failures ofthe regular source, said auxiliary source comprising a direct-currentsupply, a transformer having primary and secondary windings and avibratory contact device for supplying alternate reversed current im-.pulses from said direct-current source to the primary winding of saidtransformer such that alternating current of the desired frequency maybe supplied to said load circuit from the secondary winding of saidtransformer, said vibratory contact device comprising a pair ofresiliently mounted relatively stationary contacts and a vibratingcontact which oscillates between and alternately makes contact with therelatively stationary contact and which has an intermediateout-of-contact position of rest, an electromagnet for oscillating saidvibratory contact, a circuit for energizing said electromagnet from saiddirectcurrent source including said vibratory contact and a thirdrelatively stationary contact, the latter being movable to and fromcontacting position with said vibratory contact both when the latter isat rest and when in vibration, and relay means responsive to the voltageof said regular source of alternating-current supply for positioningsaid third contact such that it makes contact with the vibratory contactwhen the latter is at rest when the regular supply source fails,intermittently makes contact with the vibratory contact when the latteris vibratingso long as said failure continues, and ceases to makecontact with the vibratory contact in any condition when the regularsource of supply is resumed.

HENRY E. WARREN.

